000			00595nab|a22002177a|4500
999			_c62804 _d62796
001			62804
003			MX-TxCIM
005			20201027162831.0
008			200624s2013||||xxu|||p|op||||00||0|eng|d
022			_a0886-6236
022			_a1944-9224 (Online)
024	8		_ahttps://doi.org/10.1002/gbc.20066
040			_aMX-TxCIM
041			_aeng
100	1		_aGriffis, T.J. _916743
245	1	0	_aReconciling the differences between top‐down and bottom‐up estimates of nitrous oxide emissions for the U.S. Corn Belt
260			_aUSA : _bWiley, _c2013.
500			_aPeer review
520			_a[1] Nitrous oxide (N2O) is a greenhouse gas with a large global warming potential and is a major cause of stratospheric ozone depletion. Croplands are the dominant source of N2O, but mitigation strategies have been limited by the large uncertainties in both direct and indirect emission factors (EFs) implemented in “bottom‐up” emission inventories. The Intergovernmental Panel on Climate Change (IPCC) recommends EFs ranging from 0.75% to 2% of the anthropogenic nitrogen (N) input for the various N2O pathways in croplands. Consideration of the global N budget yields a much higher EF ranging between 3.8% and 5.1% of the anthropogenic N input. Here we use 2 years of hourly high‐precision N2O concentration measurements on a very tall tower to evaluate the IPCC bottom‐up and global “top‐down” EFs for a large representative subsection of the United States Corn Belt, a vast region spanning the U.S. Midwest that is dominated by intensive N inputs to support corn cultivation. Scaling up these results indicates that agricultural sources in the Corn Belt released 420±50 Gg N (mean ±1 standard deviation; 1 Gg =109 g) in 2010, in close agreement with the top‐down estimate of 350±50 Gg N and 80% larger than the bottom‐up estimate based on the IPCC EFs (230 ± 180 Gg N). The large difference between the tall tower measurement and the bottom‐up estimate implies the existence of N2O emission hot spots or missing sources within the landscape that are not fully accounted for in the IPCC and other bottom‐up emission inventories. Reconciling these differences is an important step toward developing a practical mitigation strategy for N2O.
546			_aText in English
650		7	_aNitrous oxide _2AGROVOC _94669
650		7	_aGreenhouse gas emissions _2AGROVOC _98210
650		7	_aFarmland _2AGROVOC _92006
700	1		_916744 _aLee, X.
700	1		_916745 _aBaker, J.M.
700	1		_914703 _aRusselle, M.P.
700	1		_916746 _aZhang, X.
700	1		_916747 _aVenterea, R.
700	1		_916748 _aMillet, D.B.
773	0		_gv. 27, no. 3, p. 746-754 _dUSA : Wiley, 2013. _x1944-9224 _tGlobal Biogeochemical Cycles
942			_cJA _n0 _2ddc